1. Field of the Invention
The present invention relates to an apparatus and method for sequentially performing instantaneous injection of a tracer by changing a depth within a groundwater observation well.
2. Description of the Related Art
A tracer test is a method to know the properties of hydraulic connectivity and hydraulic dispersion of a medium through the reaction morphology to a chemical impact which is in higher concentration than a background concentration. Steps of selecting a tracer, making a solution, injecting the tracer and observing/analyzing concentration change are performed to complete a tracer test. The point dilution technique is a kind of the trace test. It aims to relate the observed dilution of a tracer, introduced into a groundwater observation well, to groundwater flow.
Generally, a point dilution test is carried out after a specific section within a well is isolated by a packer and a tracer is injected into the section between the upper packer and the lower packer through a tracer injection pipe. The packer installed in the specific section in the well aims to prevent a vertical flow of groundwater in the specific section.
However, when the packer is used, a lot of equipment is increasingly needed to perform the tracer test and a lot of time and work are needed to move/install/disjoint the packer in the well. In the case where there is no vertical flow of the groundwater in the well or the vertical flow is insignificant, it is possible to perform the tracer test by injecting the tracer without installing the packer. However, in this case, since it is difficult to continue carrying the tracer, the tracer test is limited to one.